Most current Wireless Local Area Networks, WLAN, or Wi-Fi networks (WLAN and Wi-Fi being used interchangeably in the remainder of this document) are networks that exist totally separate from cellular or mobile communication networks, and can be seen as non-integrated from the perspective of a terminal or user equipment.
Most operating systems (OSs) used in user equipment, for example Android™ and iOS®, support a simple Wi-Fi offloading mechanism whereby a user equipment can immediately switch all its IP traffic to a Wi-Fi network upon the detection of a suitable network with a received signal strength above a certain level. The decision about whether or not to offload to a Wi-Fi network is referred to as an access selection strategy, and the term “Wi-Fi-if-coverage” is used to refer to the aforementioned strategy of selecting a Wi-Fi network whenever such a network is detected. There are several drawbacks of the “Wi-Fi-if-coverage” strategy.
For example, although a user can save previous pass codes for already accessed Wi-Fi Access Points (APs), hotspot login for previously non-accessed APs usually requires user intervention, either by entering the pass code using a Wi-Fi connection manager or using a web interface. The connection manager is software on a user device that is in charge of managing the network connections of the terminal, taking into account user preferences, operator preferences, network conditions, and so on.
A drawback of the Wi-Fi-if-coverage strategy is that no consideration is made of expected user experience, except those considered in a user equipment implemented proprietary solution, and this can lead to a user equipment being handed over from a high data rate mobile network connection to a low data rate Wi-Fi connection. Even though the operating system of a user equipment, or some high level software, is intelligent enough to make the offload decisions only when the signal level on the Wi-Fi is considerably better than the mobile network link, there can still be limitations on the backhaul of the Wi-Fi Access Point (AP) that may end up being a bottleneck.
Another drawback of the Wi-Fi-if-coverage strategy is that no consideration is made of the respective load conditions in the mobile network and Wi-Fi network. As such, a user equipment might still be offloaded to a Wi-Fi access point that is serving several user equipment, while the mobile network (e.g. LTE), to which it was previously connected to, is rather unloaded.
In addition, the Wi-Fi-if-coverage strategy can lead to interruptions of on-going services, for example due to the change of IP address when a user equipment switches to the Wi-Fi network. For example, a user who started a Voice over IP (VoIP) call while connected to a mobile network is likely to experience a call drop when arriving home and the user equipment switches to the Wi-Fi network automatically. Although some applications, for example Spotify®, are intelligent enough to handle this and survive the change of IP address, the majority of current applications cannot. This can place a burden on application developers if they have to ensure service continuity.
Yet a further drawback of the Wi-Fi-if-coverage strategy is that no consideration about the mobility of the user equipment is made. Due to this, a fast moving user equipment can end up being offloaded to a Wi-Fi access point for a short duration, just to be handed back over to the mobile network. This is a particular problem in scenarios such as cafes with open Wi-Fi, where a user walking by or even driving by the cafe might be affected by this. Such ping pong between the Wi-Fi and mobile networks can cause service interruptions as well as generate considerable unnecessary signaling (e.g. towards authentication servers).
Recently, Wi-Fi has been subject to increased interest from cellular network operators, not only as an extension to fixed broadband access, but also in connection with using the Wi-Fi technology as an extension, or alternative to cellular radio access network technologies to handle the always increasing wireless bandwidth demands.
At present, a WLAN node, such as an access point, has limitations when handling traffic data from a user equipment that comprises both WLAN type traffic data (such as local breakout traffic) and cellular type traffic data (such as aggregation traffic).